I have a 30 gal tank that is 30x12x12 and it was designed for the lid to slide in on grooves on the sides. I got the tank from a friend for free and he didn't have the lid anymore. I bought a lid that fits on top but its sits funny and the clamps dont do a whole lot more then a text book on top. I looked all over and I cant find anywhere that sells the lid im looking for without buying a whole new tank. What are my options? Or do any of you know where I can get that type of lid? Much appreciated!

-Taytay